In recent years, an electric power-steering device is employed in a steering device of a vehicle. An electric power-steering device is equipped to a portion around a rack axis of the steering device. An electric power-steering device of this kind transmits an output power of an actuator motor to a rack axis by using a transmission mechanism, such as a belt transmission mechanism. The actuator motor frequently inverts its rotational direction in order to move the vehicle rightward and leftward according to an intention of a driver. The transmission mechanism may employ a helical toothed device in order to reduce uncomfortableness and to enhance a feeling of a steering operation. For example, a transmission mechanism may employ a helical toothed belt pulley and a belt, a helical toothed gear pair, and/or the like.
It is noted that, in a configuration employing a helical toothed pulley, a helical toothed belt, and/or the like, a counter force works on a rotation axis in an axial direction when an actuator motor is in operation. The direction of the counter force is inverted as the rotational direction of the actuator motor is inverted. Therefore, a bearing, which supports the rotation axis, is applied with an impact when the counter force is inverted in direction.
It is an object of the present disclosure to produce an actuator motor for an electric power-steering device enabling to reduce a stress caused in a bearing, which supports a rotation axis, without enlargement of the device in a radial direction.